Fan bracket with "shelf" for mounting strips of LEDs

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Dale Reed
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Fan bracket with "shelf" for mounting strips of LEDs

Post by Dale Reed » Sat May 31, 2014 2:45 am

All,

Here's my new fan bracket for my M2 -- it has two screw holes for each fan, for secure mounting, a "shelf" for putting a couple strips of LEDs, and a 40-degree bend (instead of 45) to ensure the 50 mm fan doesn't run into the binder clips for the glass on the bed.
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There are two 3-LED strips (12 volts each), wired in series, and that all wired in parallel with the 40 mm fan (24 volt fan). Really illuminates the action, especially for those first few layers. If the print isn't starting well, you can see it and abort before you waste a bunch of filament.

Get the files at http://www.thingiverse.com/thing:348480. I designed it in OpenSCAD and printed with S3D. Just drop it on the bed and print -- no support needed, even for the holes. I used 100% infill, so it's rock solid. How I got lucky enough to have the screw holes line up perfectly --- no clue. I must have measured twice! Digital calipers are our friends.

Dale

jsc
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Re: Fan bracket with "shelf" for mounting strips of LEDs

Post by jsc » Sat May 31, 2014 4:08 am

Nice, Dale. Some questions, though. You run 3 12V LED strips in series? Then each is only getting 8V?

Also, you say it is in parallel with the 40mm fan, but unless you've disabled the electronics case fan, the 40mm fan should be getting 12V as it is in series with an identical 40mm fan.

Dale Reed
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Re: Fan bracket with "shelf" for mounting strips of LEDs

Post by Dale Reed » Sat May 31, 2014 11:49 pm

Sorry if I worded my post inexactly. I'm using two strips, 3 LEDs per strip.

If you get the spools of LEDs at Radio Shack, there's a "Push button to show me" thing on the package. I used the LEDs on the spools (two packages) for something else, and I took the "Show Me!" LEDs from the packaging and used them for this. They are pre-terminated with wires and a heat-shrink over the terminations. I just cut the wires short right at the little pushbutton switch and battery, stripped, and crimped using the connectors you see.

Two strips. Three LEDs per strip. From Radio Shack. 24 volts across two strips in series gives 12 volts per strip. If you follow the wires in the picture carefully, I think you can see how I wired it. The wires for both fans leave the photo at the upper right and are terminated in the little Molex connectors that go to the harness above the extruder. (The two-wire "cable" for the 50 mm fan is twisted so you can only see one of the wires. Follow closely from the fan up to the right.) You see three crimp splices. The one bottom front in the photo connects the red wire of one LED strip to the black wire of the other (placing them in series). The other two, above, connect the LEDs (bottom left side of crimp splices in photo) in parallel (all the reds in one splice, all the blacks in the other) with the fan and supply (upper right end of crimp splices in photo).

Note that I am using the ORIGINAL wiring harness from my 19V/12V M2, and I bought some 40 mm 24-volt fans online when I upgraded to 24 volts! ALL my fans are 24 volts. THIS IS NOT THE CASE for currently shipping M2s, so beware!!!

Sorry about the wording, Jin. ("Two 3-LED strips" in the OP) (But the photo doesn't lie! ;-) )

Was that clearer?
Dale

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helifrek
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Re: Fan bracket with "shelf" for mounting strips of LEDs

Post by helifrek » Sat Dec 27, 2014 2:29 pm

Looks great!
I have tons of these lights laying around from my RC stuff. I just got my printer this month, it is the newest version running 24V...... What would I need to splice into to get 24V?
I added lights to my last printer by gutting a small 12V ac/dc adaptor, wiring the 110V ac wires to where they connected on the power supply after the on/off switch. I printed a case for the guts of the adaptor and it worked like a charm!
I could do the same thing again but don't know if there is room inside the power supply box.... haven't opened it up (yet :) )

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Tim
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Re: Fan bracket with "shelf" for mounting strips of LEDs

Post by Tim » Sat Dec 27, 2014 8:28 pm

I'm running 12V LED lights on a 24V M2. It can be done very carefully by using two strips of LEDs in series. You have to make sure that they have exactly the same number of lights, because the voltage drop needs to be the same across each strip. It's exactly what everybody says you can't do with LED strips, and in general, that's true. But LEDs are solid-state and highly consistant from part to part, so an equal number of lights in two strips in series will divide the voltage almost exactly in two. Because I have a dual extruder, I didn't have an extra output terminal to use, so I just hooked them into the same output that drives the extruder and electronics case fans. So the LEDs are always on when the machine is on, and no fancy dimming or blinking or whatever, but it's all nicely lit up.

One unexpected downside I found is that the LED lights did not really make it much easier to level the bed, as I expected them to. There's something about the way the light reflects from the bottom of the glass, or maybe through the side, that makes it strangely difficult to tell how far above the glass the hot end is sitting. I don't know if anybody else has experience that. I put the LEDs all the way up one side, across the top, and down the other side. In retrospect, probably just across the top would have been plenty.

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helifrek
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Re: Fan bracket with "shelf" for mounting strips of LEDs

Post by helifrek » Sat Dec 27, 2014 9:55 pm

lets say for ease of wiring, I wanted to wire the lights to the extruder fan 1 plug..... would it go like this:

(I am better at soldering than I am at drawing.....)

I am using two 12V fans in series..... if I don't have to wire anything to the Rambo, that is a plus for me :)
I don't want to fry anything.
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Tim
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Re: Fan bracket with "shelf" for mounting strips of LEDs

Post by Tim » Sun Dec 28, 2014 4:07 am

You've got the right idea on the series connections of the LED strips---the + and - connections run the length of the strip, so yes, if you make connections to one end, you will leave the other end disconnected.

However, I would not recommend connecting to the fan. For one thing, if you're showing one of your 12V fans there, then you put 12V across your series LEDs, not 24V. But you don't want to do something like connect the 12V LED strip in parallel with one of the fans, because the fans are already in a delicate balance that, like the LED strips, assumes that each fan draws the same amount of current, so that two in series will divide the voltage in half (this is almost certainly less accurate for the fans than for the LEDs, but the fans have a pretty wide voltage tolerance).

Really, you *should* be connecting the wires back into the RAMBo. The green terminal blocks clamp down on the wires with screws, so it doesn't require any soldering, just a jeweler's flathead screwdriver and a bit of patience. The hard part is when you have parallel connections with both the series fans and the series LEDs, then you have to make sure the terminal block is clamping firmly down on two wires at once, and it's very easy to end up with one of the wires loose. So gently pull on the wires to see if any are loose, and be prepared to redo the connection several times. But the fan terminal block is labeled "FAN" (can't remember off the top of my head if it's 0 or 1), the fans all have red wires on + and black wires on -, and the LED strips are all clearly marked + and -, so there's not much danger of frying anything. Usually my biggest worry is melting something on the RAMBo if I have to get a soldering iron in there; using the screw terminals is more of a hassle but less of a worry.

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helifrek
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Re: Fan bracket with "shelf" for mounting strips of LEDs

Post by helifrek » Sun Dec 28, 2014 6:12 pm

Thank you for your description Tim! Once I print out Dales fan bracket I will take the print back into the hobby room to do the modification. I have a flashlight sitting next to the printer to check my prints, it is very difficult to tell how things are doing without any light in there!
I did remove the case on the power supply to see what's going on in there and if I could tie in a 12V adaptor like I did on my other printer but I didn't like how closely it would be sitting to the wire terminals. Also that would involve a lot more wiring.
So all I need to do is wire the lights into the same terminal block as the extruder/case fan and run them in series. That sounds simple enough.

Thanks again!
Brandon

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helifrek
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Re: Fan bracket with "shelf" for mounting strips of LEDs

Post by helifrek » Fri Jan 09, 2015 9:45 pm

Just an update.
I finally got a chance to print out the new bracket and run the wires into the fan connector, or connector..... not sure what the technical term is for that thing. Anyways, looks very professional! added a JST connector and heatshrinked the wires to match the fan and heater wires. Only problem was the leds kept coming unstuck, so I epoxied them in place. I will try to add some pics when I get the time.

Thanks again for the bracket design Dale and for the great wiring description Tim!

One more thing about the bracket design that I like is that it seems to put more airflow at the nozzle where it needs it and there is no chance of the fan hitting the binder clips now!

Dale Reed
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Re: Fan bracket with "shelf" for mounting strips of LEDs

Post by Dale Reed » Sat Jan 10, 2015 2:43 am

helifrek,

Thank you very much for your kind words. I did try to make the angle such that the fan would not hit the binder clips at the front of the bed. I did not make any attempt to optimize the aim at the tip of the nozzle, however, so I'm glad that aspect worked out well for you. Enjoy!

Dale

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